Improvement in molds for steel castings



rh PETERS. PHOTO-LITHOGRPHER, WASHINGTON D C PERRY G. GARDINER,

Paritair @erica or NRW YORK, N. Y.

IMPROVEMENT IN iVlOLDS FOR STEEL CASTINGS.

Specification forming part ofvLetters Patent No. 23.670, dated April i9, 1859.

AO all whom ttm/ty concern.'y

Beit known that I, PERRY G. GARDINRR, ot'k the city of New York, N. Y., have invented new and useful Improvements in Molds for Gastin g Steel into Ingots, Tools, YVheels, Instruments, or other Castings, and in the treatment there of for receiving and holding the molten metal, and I do hereby declare that the following` is a full and exact description of my said improvements, and ofthe manner of making and using the same, reference being had to the drawings accompanying and making part of this my specification.

The object of my improvements is to produce the casting, whether it be aningot, or an instrument, tool, or other article of steel, of a uniform, compact, and homogeneous charac ter, free from cracks, bubbles, oxidation land its ei-Iects, and other deteriorating` circumeumstances common to the usual processes ot' casting steel. Then steel is at the intense degrec ot' heat at which it becomes molten, it is liable to oxidation from the atmosphere, and especially so when, in'pouring into a mold, the external air becomes mixed with it or remains with it, and while it is setting or cooling it is also apt to bubble or "become spongy within the casting or on its surface, so as to injure its quality, as well as deface it. Such defects and deteriorations also affect the steel, when cast into an instrument or tool, in its capacity for being polished or finished. IVhen molten steel is poured into a moldin the usual way, it instantly produces an immense expansion of the air, which escapes with great violence and rapidity through such vents as are in common air, but in so doing voften produces agitation, spouting, honeycombing, or sponginess, and the operation is also attended with danger to the workman. The character and quality of the steel produced from a east will depend partly upon the circumstances under which it is reduced into the molten state; secondly, upon the temperature, material, form, and adaptation of the mold in which the cast is made, and, thirdly, upon the cooling it gradually away from the external atmosphere, and in a bath of oil or other fluid more or less heated.

My present improvements relate to the molds and the manner of constructing and using them, the other stages not being empraced in this specification.

In the accompanying drawings, Figure I rep resents my improved mold in section through the center of the parts which are to receive the metal and form the tool. (In the present case it is a mechanies hammer.) Fig. II is a top or surface view oi' the mold, the line #c representing the line of separation of the two parts of the mold, and also the plane of the section shown in Fig. I. Figs. Ill IV represent longitudinal and cross sections of movable plugs or valve-stoppers fitted to and used in the corresponding parts of the molds, as hereinafter particularly described. Y

In all the gures the same letters represent the same parts.

Fig. I represents the shape of the mold,

and also, in section, the parts which are to secure the melted steel, and to which my improvements in part relate.

rIhe mold is made in two equal parts, as is usual in Vmolds for castings, and the two parts wheirput together form a complete pattern for the casting intended to be produced, and also the parts for receiving the molten metal and for the discharge of the air.

The mold may be made of black-lead, iireclay, or any material that will admit of being heated toa very high degree of heat, (never less than 5000'of Fahrenheit,) and which at the same time is a bad conductor of heat. If iron or any similar metal is used, it must be coated or lined where the melted steel comes in contact with the mold with some non-conductor of heat, such as plumbago, platinum, &c.

Neither molding sand nor loam are suitable materials for my improved molds.

In the top of the mold I make a cup or reservoir, a, like an inverted hollow cone the Yapex ot' which is cut off, and opens into the sprue or the conduit Z), which is bent at its lower extremity, so as to lead directly to the bottom of the mold for the tool or instrument to be-cast.

In the drawings the tool intended to be cast is a meehanicis hammer, c c.

The lines c e represent a cone for forming the eye or orifice for receiving the handle of the hammer.

In all cases it is best that the melted steel should run into the pattern or figure from below, and I construct my mold and the parts which receive the metal so that the cup a, the

sprue b, and the pattern o, figure, and the airchambers and valves constitute an inverted bent tube, the ends or surfaces of which are in the top of the mold, and on the same level or plane, the conduit or sprue forming part of one leg of the bent tube, and the figure for the casting or pattern of the other leg.

Above the space for the casting I construct the spherical hollow d, which communicates with the space for the casting underneath by the opening d, and which opens upward through the conical-shaped opening or cup d. The cup or reservoirashould be of a capacity to hold sufficient of the melted metal to form the entire. casting and enough over to fill the sprue.

Fig. III is a stopper or plug, e, made to iit the bottom of the cup a and the upper part of the sprue b, so as to close the passage entirely when necessary and open it by raising the plug, which is done by the long handle e, attached to the stopper. c is a horizontal section of plug e. The use of this, in connection with the cup or reservoir, is to regulate the iiow of the melted metal into the mold and to cut off the ilow when required, so as not to allow the external air to get into the mold, which is done by lling the cup full of the melted metal, the plug or stopper being first put into its place, so as to shut off the passage into the sprue, and when the metal is to bein troduced into the mold by lifting the plug a little, so as to allow the flow of the metal, but not the admission of the'external air. rIhis plug or stopper and the plug f, hereinafter described, are to be made of some material or composition which Will stand interior heat, to which they are to be subjected.

Fig. IV represents the stopperj" of the cup or chamber d, f being a vertical section, and f a horizontal section, through the stopper. The smaller endvoff iits into the opening in the top of the spherical chamber CZ, so as to close it. Upon the sides of this stopper are grooves or fastenings l 2. Vhen the casting is made, the heated air from the mold lifts the stopper f a little and the air escapes readily by the ieetings without th rowing out the stopper, and as soon as the air ceases to lift the stopper it falls and closes the passage to the mold and entirely excludes the external air from this end of the mold. Wvhen the casting is to be made, the mold must be heated up to a very intense degree of heat, never less than 500 of Fahrenheit, and it is better that at the time of pouring in the metal the mold should beat about 2,000o or 2,500o Fahrenheit of temperature. The great heat of the mold varies the air Wit-hin the mold, so as to make it thin,

approaching to a vacuum, andthe plugs or Stoppers e f being placed in their places, the melted steel is to be poured into the cup or reservoir, or so as to fill it. The effect of the plugs is thus to cut off all communication with the external air. The plug f bein g raised a little-mot however above the surface of the metal in the cup-the metal iiows down the sprue and rises into the mold, lling it completely, and as soon as this is done the flow of the metal is stopped by shutting down the plug e. Should the air be still more rareed by the metal within the mold than before, by heating the mold it will rise into chamber d and pass off through d by lifting the stopper f until it ceases to expand, when the passage is immediately closed by the falling of stopper f, as before described. Ingots, tools. and instruments cast in this manner from steel will be of the uniformity, compactness, and solidity so greatly desired in all castings of steel for such purposes, and without which the tool, instrument, or ingot cannot be made perfect by any subsequent process or treatment of hardening, annealing, hammering, or finishing or polishing, but will always be de fective in substance and in appearance.

Having thus described my improvements, what I claim therein as my invention, and for which l desire Letters Patent, is-

l. The constructing the mold with a cup or reservoir for holding all the melted metal for the casting, closed and opened at the entrance of the sprue by the movable plug or stopper, as described. i

2. The spherical hollow chamber d and airescape passage t, and seliacting plug f, to permit the rareed air to pass from the mold and to escape, and to shut off the external air from the mold, operating in the manner and for the object described.

3. The combination and arrangement of the two cups, the sprue, the figure 0, the tool or casting, and air vents or passages, so as to form a bent tube by which the casting is iilled from the bottom 'and the external air excluded, as described.

4. The use of the molds in ast-ate of intense heat, never less than 500o of Fahrenheit, and generally at a much higher temperature, for the purpose of producing, as nearly as practicable, a Vacuum within the mold; but I do not claim the mere heating or warming of the molds to produce a smooth casting, that having been a common practice heretofore.

P. G. GARDINER.

Vitnesses:

J. B. STURenss, Guo, W. FOX. 

